minimal cpu exception handling

1 files changed, 119 insertions, 0 deletions

diff --git a/kernel/interrupts.cpp b/kernel/interrupts.cpp
new file mode 100644
index 0000000..65daf91
--- /dev/null
+++ b/kernel/interrupts.cpp
@@ -0,0 +1,119 @@
+#include <mercury/kernel/terminal.hpp>
+
+using namespace mercury::kernel;
+
+struct [[gnu::packed]] exception_info_t {
+
+  uint64_t rax;
+  uint64_t rbx;
+  uint64_t rcx;
+  uint64_t rdx;
+  uint64_t rdi;
+  uint64_t rsi;
+  uint64_t rbp;
+  uint64_t rsp;
+  uint64_t r8;
+  uint64_t r9;
+  uint64_t r10;
+  uint64_t r11;
+  uint64_t r12;
+  uint64_t r13;
+  uint64_t r14;
+  uint64_t r15;
+
+  uint64_t cr3;
+  uint64_t rip;
+  uint64_t rflags;
+
+  uint64_t error;
+  uint8_t has_error;//0 or 1
+  uint8_t exception_number;
+
+};
+
+extern exception_info_t exception_info;
+
+const char *exception_types[] = {
+  "division error",
+  "",
+  "non-maskable interrupt",
+  "",
+  "",
+  "",
+  "invalid opcode",
+  "",
+  "double fault (uh oh)",
+  "",
+  "",
+  "",
+  "stack fault",
+  "general protection fault",
+  "page fault",
+  ""
+};
+
+const char *flag_names[] = {
+  " cf",
+  "",
+  " pf",
+  "",
+  " af",
+  "",
+  " zf",
+  " sf",
+  " tf",
+  " if",
+  " df",
+  " of",
+  "",
+  "",
+  " nt",
+  " md"
+};
+
+void print_line(const char *r1, const char *r2, uint64_t r1v, uint64_t r2v) {
+  terminal::put_string_sz("\n  ");
+  terminal::put_string_sz(r1);
+  terminal::put_string_sz(": 0x");
+  terminal::put_int_hex(r1v, 16);
+  terminal::put_string_sz("  ");
+  terminal::put_string_sz(r2);
+  terminal::put_string_sz(": 0x");
+  terminal::put_int_hex(r2v, 16);
+}
+
+extern "C" [[noreturn]] void print_exception() {
+
+  terminal::put_string_sz("exception handler:\n  type: ");
+  terminal::put_string_sz(exception_types[exception_info.exception_number]);
+  terminal::put_string_sz(" (0x");
+  terminal::put_int_hex(exception_info.exception_number, 2);
+  terminal::put_char(')');
+
+  if (exception_info.has_error == 1) {
+    terminal::put_string_sz("\n  error code: 0x");
+    terminal::put_int_hex(exception_info.error, 16);
+  }
+
+  terminal::put_string_sz("\n  flags:");
+  if (exception_info.rflags == 0)
+    terminal::put_string_sz(" [none]");
+  else
+    for (int i = 0; i < 16; ++i)
+      if (((exception_info.rflags >> i) & 1) == 1)
+        terminal::put_string_sz(flag_names[i]);
+
+  print_line("rip", "cr3", exception_info.rip, exception_info.cr3);
+  print_line("rax", "rbx", exception_info.rax, exception_info.rbx);
+  print_line("rcx", "rdx", exception_info.rcx, exception_info.rdx);
+  print_line("rdi", "rsi", exception_info.rdi, exception_info.rsi);
+  print_line("rbp", "rsp", exception_info.rbp, exception_info.rsp);
+  print_line("r8 ", "r9 ", exception_info.r8 , exception_info.r9 );
+  print_line("r10", "r11", exception_info.r10, exception_info.r11);
+  print_line("r12", "r13", exception_info.r12, exception_info.r13);
+  print_line("r14", "r15", exception_info.r14, exception_info.r15);
+
+  while (1)
+    asm ("hlt");
+
+}